Of all the surrounding issues and questions, the only question that matters is "Why did he point the gun at her and fire?" Even if by some one in a million chance the gun misfired while he pointed it at her, why did he ever point the gun at a person? That is a deliberate action. The gun didn't point itself at her. He did that. Why?
Precisely, especially when it should have been common knowledge on the set that this is, in fact, a "real" gun, not just some prop. It was used for recreational shooting off set. As such, there are many failures in this, first that the gun was not completely cleared off set, and that no live ammo should have been on set. Second, the gun should have been checked before it was issued to him (which raises the question of whether it had been, or if it was issued or he just grabbed it). Third, on receipt of the firearm, he, personally, should have verified that it was not loaded with live ammo. If he was at any point unsure of the nature of the ammo in it (blank vs live) he should have consulted with the armorer to verify the nature of that ammo. Fourth, since even blank ammo can cause injury, he never should have pointed the gun at anyone. Fifth, to have failed in the fourth,
and to pull the trigger, is an egregious violation of gun handling safety in any venue.
As much anti-gun screed as Mr. Baldwin has subjected the millions of firearm owners who get it right daily, he, of all people, should have exercised the ordinary due caution one would expect of anyone handling firearms.